Differential expression of HLA-DR, HLA-DP, and HLA-DQ antigenic determinants of the major histocompatibility complex in human endometrium.

We reported on the expression of HLA-DR molecules of the major histocompatibility complex in human endometrium. We now report on the expression of two other class II molecules, the HLA-DP and HLA-DQ determinants. These molecules were localized by monoclonal antibodies in 11 proliferative and 12 secretory endometria by avidin-biotin-complex (ABC) procedure. The expression of all three molecules was invariable and consistent throughout the entire menstrual cycle in endothelial and lymphoid cells. HLA-DR molecules were expressed in endometrial epithelium, particularly in the basalis in the mid to late proliferative phases of the cycle. In contrast, through the entire menstrual cycle, the expression of HLA-DP and HLA-DQ antigenic determinants was absent, and only occasionally a focal expression of these molecules was seen in endometrial epithelium. The in vitro induction of expression of the class II molecules in human endometrial epithelial cell cultures (HEE) by IFN-gamma was dose-dependent. After treatment with low doses of IFN-gamma, these cells primarily expressed HLA-DR molecules in vitro. The differential expression of the molecules of the major histocompatibility complex in human endometrial epithelium in vivo may be due to the differential sensitivity of th epithelium in response to cytokine(s).